Field of the Invention
The present invention relates to an operation device for a link actuating device to be used in an apparatus, such as an industrial apparatus, that requires a precise and wide operating range. More particularly, the present invention relates to an operation device that can be effectively used when the link actuating device is used with an end effector being mounted to a distal end thereof.
Description of Related Art
Conventionally, as a parallel link mechanism of a link actuating device that has a compact structure but realizes a wide range of movement of a distal end side link hub, a parallel link mechanism 1 shown in FIGS. 10, 11A, and 11B has been suggested in which a distal end side link hub 3 is connected to a proximal end side link hub 2 via three or more link mechanisms 4 such that the posture of the distal end side link hub 3 can be changed relative to proximal end side link hub 2 (for example, Patent Document 1).
In such a link actuating device, the posture of a device that drives the two-degrees-of-freedom parallel link mechanism 1 by three or more motors is determined by a bend angle θ and an angle of swing ϕ. That is, an rotation angle (β1n, β2n, β3n) of each arm is obtained from the bend angle θ and the angle of swing ϕ, and an actuator that drives the arm is caused to determine the position of the arm. For example, regarding a distal end posture A(θa, ϕa) and a distal end posture B(θb, ϕb) of a specific link hub 3, the arm rotation angles corresponding to the respective distal end postures are obtained as A(β1a, β2a, β3a) and B(β1b, β2b, 3b) according to a relational expression between the link hub and the arm rotation angles. Movement from the distal end posture A to the distal end posture B is executed by the respective arm rotation angles being changed from β1a to β1b, from β2a to β2b, and from β3a to β3b. It is noted that in FIGS. 10 and 11, the same reference numerals are assigned to the portions corresponding to those shown in FIGS. 1 to 9 according to an embodiment of the present invention described later.
In Patent Document 1, from a rectangular coordinate system 100 which is set on an extension of the posture of the link actuating device, the distal end posture (bend angle θ, angle of swing ϕ) of the link hub 3 is obtained by using convergence calculation by the method of least squares. This enables positioning of an end effector to arbitrary coordinates on a work surface (rectangular coordinate plane) on which the end effector works.